Auto manufacturers are investigating radar, lidar and vision-based pre-crash sensing systems to improve occupant safety. Pre-crash sensing systems have been recognized to have the potential of improving occupant safety by deploying the passive restraints devices earlier in a crash, or even before the actual impact. This extra time allows more flexibility for component design and can allow the passive restraints system to be individually tailored to the occupant and crash scenario.
Existing pre-crash sensing systems present challenges that make it difficult to adapt said systems for side-impact applications. Vision and radar systems, for example, can be relatively expensive and difficult to package due to space constraints. Additionally, existing systems for blind-spot detection and lane change assistance present challenges because of the limited field of coverage for the sensors used in those systems. In particular, sensors in those systems are adapted to detect cars and trucks in adjacent lanes toward the rear of the vehicle. Such field of coverage is incomplete for side-impact applications because most side-impact collisions are caused by vehicles coming from side-frontal directions.
Additional challenges exist regarding side-impact sensing systems. In particular, because there are often vehicles traveling in adjacent lanes, it is difficult to avoid false-positive alarms in a side-impact sensing system.
Also, an analysis of the National Automotive Sampling System (NASS) accident database shows that a majority of side-impact collisions occur when a host vehicle is traveling at a speed of less than 40 kilometers per hour. In fact, this NASS database analysis, which includes data from 1995-2007, indicates that 62% of side-impact collisions occur when the host vehicle is traveling at a speed of less than 40 kilometers per hour.
It would therefore be desirable to provide a side-impact sensing system that provides accurate determinations as to the presence of a potential side-impact collision impactor. It would also be desirable to provide a system that is relatively inexpensive and that can be incorporated into existing vehicles and combined with existing systems with relative ease. It would also be desirable to provide a system that is able to detect potential side-impact collisions when the host vehicle is traveling at a speed of less than about 40 kilometers per hour.